Foveavelia, a new South American genus of Veliinae (Hemiptera: Heteroptera: Veliidae)

Background Semiaquatic bugs (Hemiptera: Heteroptera: Gerromorpha) are distributed worldwide and play fundamental roles in limnic ecosystems. They are the most successful group of organisms to occupy the air-water interface, are important models to study ecology and evolution, and can be relevant tools in biomonitoring. Veliidae is the second most speciose family of semiaquatic bugs, but its internal classification, including subfamilies and genera, is artificial and based on symplesiomorphies. One of these non-monophyletic entities is Paravelia Breddin, 1898, the largest genus in the subfamily Veliinae. Results In an effort to better classify the Veliinae, we describe Foveavelia to hold five South American species previously placed in Paravelia. The new genus is characterized by the following combination of features: unusual coarse cuticular punctures throughout the thorax and abdomen; a pair of small, frosty, pubescent areas formed by a very dense layer of short setae on the anterior lobe of the pronotum; fore tibial grasping comb present only in males; middle tibia with a row of elongate dark-brown trichobothria-like setae on the distal third, decreasing in size distally; macropterous specimens with the apical macula of the forewings elongate and constricted at mid-length, reaching the wing apex; and the male proctiger with a pair of anterodorsal projections. Besides the description, a key to the species of Foveavelia is provided, accompanied by illustrations and a species distribution map.


INTRODUCTION
Veliidae (Hemiptera: Heteroptera: Gerromorpha) is a family of small to medium-sized insects that live predominantly on the surface of the water.Some of them occur on stagnant waters, such as lakes and puddles, while others occupy rivers and streams, and a few can be found in terrestrial environments relatively far from the water (Schuh & Slater, 1995).Andersen (1982) established a phylogeny for Veliidae based on morphology and proposed the division into six subfamilies: Haloveliinae, Microveliinae, Ocellloveliinae, Perittopinae, Rhagoveliinae and Veliinae.Subsequently, Damgaard (2008) proposed a phylogeny for Gerromorpha based on morphological and molecular data.He demonstrated that the subfamilies Microveliinae and Haloveliinae were actually closer

Morphological study
All measurements are given in millimeters.Antennomeres and abdominal segments numbers are expressed as Roman numerals.We used standard entomological techniques to examine the morphology of the specimens used in this study.Abdominal segment VIII and genital capsule of the males were removed using forceps and an entomological pin, without the need for clarification.Photographs have been obtained using a Leica DFC420 camera attached to a LeicaM165C binocular microscope, processed with the Leica Application Suite V3.7.0, and stacked using Auto-Montage.Scanning electron microscopy photographs have been provided by Dr. Silvia Mazzucconi.All final figures have been prepared using Adobe Photoshop CS6.

Nomenclatural acts
The electronic version of this article in Portable Document Format (PDF) will represent a published work according to the International Commission on Zoological Nomenclature (ICZN), and hence the new names contained in the electronic version are effectively published under that Code from the electronic edition alone.This published work and the nomenclatural acts it contains have been registered in ZooBank, the online registration system for the ICZN.The ZooBank LSIDs (Life Science Identifiers) can be resolved and the associated information viewed through any standard web browser by appending the LSID to the prefix http://zoobank.org/.The LSID for this publication is: (urn:lsid:zoobank.org:pub:DAAB68B0-7AB5-4D92-AAE8-A9051CD9EC11).The online version of this work is archived and available from the following digital repositories: PeerJ, PubMed Central SCIE and CLOCKSS.

Description
Medium-sized veliids; macropterous or brachypterous (micropterous and apterous forms unknown); ground color brown, covered by golden pubescence, with faint yellowish annulations on femora.Body moderately robust, length 4.80-6.50mm; general characteristics and size not sexually dimorphic (Figs. 1,7), except for F. dilatata .Head: Declivant anteriorly, not recessed into pronotum, with usual three pairs of trichobothria and impressed median line; posterodorsal region with a pair of narrow, posteriorly convergent, impressed lines located between impressed median line and elliptical indentation on each side (Fig. 2A); gula and buccula with several suboval, coarse punctures; gular region visible (Figs.7B, 7D-7E).Eyes globose, separated by more than an eye width, slightly removed from anterior margin of pronotum; ocular setae present.
Labium extending onto anterior region of metasternum; article I almost reaching posterior margin of bucculae; articles I and IV subequal in length, each longer than article II; article III about seven times as long as II (Fig. 1D).Antennae densely covered by golden pubescence and long brown setae; antennomere I thickest, curved laterally; II slightly thicker than III-IV; III-IV subequal in width; IV filiform (as in Fig. 1).
Foveavelia is defined by the following combination of characteristics: (1) the unusual coarse cuticular punctures found throughout the thorax and abdomen (Fig. 2); (2) the pair of small, frosty pubescent areas formed by a very dense layer of short setae on anterior lobe of the pronotum (Figs.1A, 4A, 4B, 4D, 4E); (3) the fore tibial grasping comb present only in males, occupying 1/6 (Fig. 1D) to 1/2 of the fore tibial length; (4) the middle tibia with a row of elongate dark-brown trichobothria-like setae on the distal third, decreasing in size  diagnostic feature of Foveavelia is the presence of coarse cuticular punctures along the body (Fig. 2).As described by Mazzucconi (2000), these structures are cuticular depressions with deep, transverse grooves, and a sensilla-like seta placed eccentrically to these grooves, or sometimes centrally.Although the arrangement of this seta varies, its size is similar among different punctures.Unlike the structure described above, the pronotal punctures typical of most Veliidae, including Foveavelia, are rounded and covered by a cluster of centrally directed microtrichia along the puncture rim, making the transverse grooves and sensilla-like seta difficult to see (Figs. 2A, 2B).On the other hand, the distinctive punctures of Foveavelia lack clusters of microtrichia along the puncture rim (Figs.2D-2E).These punctures usually do not touch each other (Figs.2C, 2F), although in some regions of the body, such as on the sides of abdominal mediotergites I-III, they are conjoined, forming larger, flower-like structures (Figs.2A, 2D).Because Paravelia is not monophyletic and due to the morphological heterogeneity among its species, it is difficult to detect diagnostic characters for the entire genus.Paravelia basalis (Spinola, 1837) (Fig. 8A), the type species, differs from Foveavelia in several characteristics, including the absence of coarse cuticular punctures throughout the body, the absence of frosty pubescence on the anterior lobe of the pronotum, the different shape and color of the forewing maculae, the presence of a pair of distinct projections on male abdominal sternum VII, the different shape of male abdominal segment VIII (Figs. 8B, 8C), and the presence of anterodorsal and anterolateral projections on the male proctiger (Fig. 8D).
Paravelia foveata Polhemus & Polhemus, 1984 (Figs. 8F, 8G) displays a pattern of cuticular punctures on the body similar to Foveavelia.However, because this species has several characteristics that are not present in other species here assigned to Foveavelia, it is not included in the new genus.The following features are exclusive to P. foveata: (1) general body color reddish-brown, with short pubescence; (2) antennomere IV very small, fusiform; (3) anterior lobe of pronotum with a pair of yellowish-white markings; (4) forewings with differently shaped closed cells, with an additional macula basally, and apical macula crescent-shaped, not reaching wing apex; (5) male fore tibial grasping comb occupying about two-thirds of the tibial length (Fig. 8G); (6) row of elongate dark-brown trichobothria-like setae on the middle tibia occupying half of the segment; (7) coarse
punctures present on abdominal sternum VII; and (8) male proctiger without anterodorsal projections.The cuticular modifications found along the body of P. foveata, especially those present on the abdomen, are very likely not homologous to those displayed by Foveavelia.Cuticular modifications similar to those of Foveavelia, but probably also not homologous, are found in members of Microveliinae (Gerromorpha: Gerridae), such as Neoalardus typicus (Distant, 1903) and Hebrovelia singularis Lundblad, 1939.Diagnosis.Body length 4.80.Pronotum rhomboid.Distance between basal and apical forewing maculae greater than length of basal macula.Forewing basal macula of macropterous specimens elongate (Fig. 1A).Male abdominal sternum VII without pair of medial gibbosities; pair of posterior rounded lobes almost at level of posterior margin.Male proctiger with a pair of rounded-lobe projections anterodorsally.Paramere with laterodorsal margin slightly convex in lateral view (Fig. 3E).Type locality.Brazil: Amapá: Santana, Porto Santana, I.C.O.M.I.Repository.The male holotype was deposited at the Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.However, it was destroyed together with most of the entomological collection of the institution in the 2018 fire (Kury, Giupponi & Mendes, 2018).Published records.Brazil: Amapá (Rodrigues et al., 2014).Distribution.This species is known only from the type-locality (Fig. 9).The acronym I.C.O.M.I. refers to "Indústria e Comércio de Minérios S/A", a mining company that was contracted by the government of the state of Amapá in the 1950s to build an ore loading dock at Porto Santana, on the estuary of the Amazon River (Bastos, Valente & Oliveira, 2021).Discussion.This species was described based solely on the male holotype and some structures (e.g., tibial grasping comb, thoracic sterna, abdominal tergum VIII) were not examined, either because the specimen was glued to a paper card or because it was not possible to dissect the male abdominal segment VIII.The diagnostic features used here to separate it from congeners need to be better studied when more specimens become available, since variations are expected.In the original description, the authors neglected the pair of small lobes present near the posterior margin of male abdominal sternum VII (Fig. 3A), which are similar to those of P. bilobata (Fig. 3B).
Foveavelia anta (Mazzucconi, 2000) n. comb.Distance between basal and apical forewing maculae greater than length of basal macula.Forewing basal macula of macropterous specimens elongate.Male fore tibial grasping comb occupying 1/6 of the tibial length.Male abdominal sternum VII with a pair of medial gibbosities (see Mazzucconi, 2000, page 131, fig. 10); posterior margin without pair of rounded lobes.Male proctiger with a pair of distinct, divergent, spinose projections anterodorsally (Fig. 3F).Paramere with laterodorsal margin sinuous in lateral view, widened at middle (Fig. 3F).Type locality.Argentina: Salta: Anta, 50 km East of Las Lajitas.Repository.Museo Argentino de Ciências Naturales "Bernardino Rivadavia", Buenos Aires, Argentina.Published records.Argentina: Salta (Mazzucconi, 2000).Paraguay: Concepción (Mazzucconi, 2000).Distribution.The two records of this species are located in the Río de La Plata basin, in southern South America (Fig. 9).Foveavelia bilobata (Rodrigues et al., 2014)  Diagnosis.Body length 5.03-5.07.Pronotum rhomboid.Distance between basal and apical forewing maculae greater than length of basal macula.Forewing basal macula of macropterous specimens elongate (Figs.1B, 1C).Male fore tibial grasping comb occupying 1/4 of tibial length.Male abdominal sternum VII without pair of medial gibbosities; pair of posterior rounded lobes extended further than posterior margin (Fig. 3B).Male proctiger with a pair of bilobed projections anterodorsally.Paramere with laterodorsal margin sinuous in lateral view, widened at posterior half (Fig. 3G).Type locality.Brazil: Mato Grosso: Nova Xavantina, Reserva Biológica Municipal Mário Viana (Parque Municipal do Bacaba), Córrego Bacaba.Repository.DPIC.macropterous male, and Rodrigues & Moreira (2016) illustrated the brachypterous female.The size and shape of the forewing maculae change according to the wing condition.In macropterous specimens, the basal and apical maculae are larger; the basal macula is roughly ovate and the apical macula is elongate and slightly constricted at mid-length (Fig. 4E).The maculae can be smaller and fainter in brachypterous specimens (Figs.4A, 4B, 4D, 5A); the basal macula, when present, is oval, and the apical macula can be small and rounded (Figs.4B, 4D) or display the typical shape seen in macropterous specimens (Fig. 4C).Paravelia hungerfordi: J. Polhemus, 1976: 512 (changed combination).Diagnosis.Body length 4.80.Pronotum rhomboid.Distance between basal and apical forewing maculae smaller than the length of the basal macula (Fig. 7A).Forewing basal macula of macropterous specimens elongate.Type locality.In the original description, the authors mentioned only "Chapada, Brazil", without additional data.The locality very likely corresponds to Chapada do Guimarães, state of Mato Grosso, and the type material was probably collected by Herbert Huntington Smith (Moreira et al., 2011).Repository.Carnegie Museum of Natural History, Pittsburgh, United States.Published record.Brazil: Mato Grosso (Drake & Harris, 1933).Distribution.Known only from the type-locality in central-western Brazil (Fig. 9).Discussion.Drake & Harris (1933) described this species based on two female specimens.Because only the type series is known, the comparison with males of other species is not possible.Mazzucconi (2000) provided a redescription of this species and compared it with F. anta.She distinguished the two based mainly on the length and width of the body, the shape of the anterolateral margin of the pronotum, and the size of the forewing maculae.Females of Foveavelia are very similar and the condition of the forewing maculae is the only viable character to identify F. hungerfordi.
all taxa with cuticular modifications, including Stridulivelia, Foveavelia and P. foveata are closely related.

CONCLUSIONS
After examination of all american species within the subfamily Veliinae, a new Neotropical genus has been established to accommodate five species previously classified in Paravelia.This new genus has been characterized morphologically using SEMs and photographs.Future phylogenetic hypotheses are required to elucidate the closely related lineages of this new genus.

Table 1
Checklist of species of Foveavelia.